A coalition of 16 US states led by California is suing President Donald Trump’s administration over his decision to declare an emergency to raise funds for a Mexican border wall.
The lawsuit was filed in the court for the Northern District of California.
It comes days after Trump invoked emergency powers to bypass Congress and secure funding for the project – a key campaign pledge.
Democrats have vowed to contest it “using every remedy available”.
California Attorney General Xavier Becerra said they were taking President Trump to court “to block his misuse of presidential power”.
The lawsuit filed on Monday seeks a preliminary injunction that would stop Trump acting on his emergency declaration while a legal battle takes place in the courts.
Trump announced the plan after Congress refused funding for the wall.
Governor Gavin Newsom of California dismissed the president’s decision as “political theatre” while New York state’s Democratic attorney general, Letitia James, promised to “fight back with every legal tool at our disposal”.
Joining California in the lawsuit were Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Minnesota, Nevada, New Jersey, New Mexico, New York, Oregon, Virginia and Michigan.